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The U.S. makes a commitment to deepen its existing carbon-cut pledge by 2025, while China says its emissions will peak by 2030. Both target coal.

By John H. Cushman Jr., InsideClimate News

Nov 12, 2014

President Obama meets staff and their families at the U.S. Embassy in Beijing, China, on Nov. 10, 2014. At a multinational summit in Beijing on Nov. 11, the U.S. and China announced new plans to deepen their carbon cuts as part of UN climate change treaty talks. Credit: White House photo/Pete Souza

The United States and China announced new goals for reducing their global warming pollution in the coming decades, with the U.S. ramping up its rate of decarbonization in five to 10 years and China promising that its carbon emissions will peak in the next 15 years.

The U.S. and China produce about a third of the total annual emissions of carbon dioxide, the principal greenhouse gas. Both have set out plans to reduce emissions, especially by using less coal in the production of electricity. Their new pledges would deepen those commitments.

"President Obama announced a new target to cut net greenhouse gas emissions 26-28 percent below 2005 levels by 2025," the White House said. "At the same time, President Xi Jinping of China announced targets to peak CO2 emissions around 2030, with the intention to try to peak early, and to increase the non-fossil fuel share of all energy to around 20 percent by 2030."

Obama, by making a concrete pledge aimed at the year 2025, was advancing the negotiating stance taken by the U.S. in the Paris treaty talks, which resume in Lima next month. The U.S. thinks it would be best for countries to set targets for the year 2025, not for later years.

China, though, knows it will take time to turn around its energy economy, so it chose a 2030 target. Even so, its commitment to reach peak emissions as soon as that year is significant. Until now, China has not committed to absolute limits on its pollution, but has instead spoken of reducing its emissions intensity—the amount of pollution it emits per unit of economic activity.

Obama's target year won't arrive until after his successor's first term in office. So, in effect, he's trying to lock in a pathway of declining carbon emissions.

From 2020 to 2025, during what might be the second term of Obama's successor, U.S. emissions would decline about 2.5 percent a year, twice as fast as in the past decade.

That is the kind of reduction required if the world is to achieve the complete decarbonization of energy systems, which mainstream scientists and international institutions say is needed to avoid the most severe risks of climate change.

"These targets will require major undertakings by both countries," said Bob Perciasepe, president of the Center for Climate and Energy Solutions, a Washington think tank. "In the case of the United States, the new target is pushing the limits of what can be done under existing law. We can get there if Congress doesn't stand in the way...But to go much further, we'll ultimately need Congress to act."